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Planothidium haynaldii

(Schaarschmidt) Lange-Bert. 1999      Category: Monoraphid
BASIONYM: Achnanthes haynaldii Schaarschmidt 1881
SYNONYM(S): Planothidium lanceolatum var. haynaldii (Schaarschmidt) Bukht. | Achnanthes lanceolata var. haynaldii (Schaarschmidt) Cleve  

Planothidium frequentissimum


Planothidium holstii

LM scalebar = 10 µm = 80 pixels.


Contributor: Marina Potapova - March 2011
Length Range: 9-25 µm
Width Range: 4.8-7.0 µm
Striae in 10 µm: 14-15


Valves are lanceolate to elliptical-lanceolate with capitate apices; specimens at the small end of the size range are nearly elliptical. The raphe valve has a linear axial area and central area that varies in shape - from transversely rectangular to elliptical. The rapheless valve has a linear-lanceolate axial area that slightly widens in the center. The asymmetrical central area on the rapheless valve contains a rimmed depression on the internal valve surface.The raphe is straight with expanded external proximal endings. Terminal raphe fissures are curved to the secondary valve side. The striae are multiseriate and radiate throughout both valves.

This page follows the concept presented in Patrick and Reimer (1966). However, recent investigation of the type material Achnanthes haynaldii (Wetzel et al. 2014) shows that that this taxon page requires revision.

Original Description

Basionym: Achnanthes haynaldii
Author: Schaarschmidt 1881
Length Range: µm
Striae in 10 µm: 14

Original Description

A. minuta, solitaria vel 2-3 in fascias conjuncta, lateribus anguste linearibus, leniter genuflexis; valvis oblongo-ellipticis apicibus rotundatis, vel elliptico-lanceolatis sub polis leniter constrictis, medio inflatis, - vel cymbiformibus, medio valde tumidis, ventricosis, utroque fine porrectis, apicibus obsolete capitatis, rotundatis; nodulo centrali valvae inferioris lateraliter dilatato duam fasciam semitransversalem Vformem referent, linea media recta, striis transversis subradiantibus distinctis, subtilibus circa 140 in 100 μ.

Original Images

Cite This Page:
Potapova, M. (2011). Planothidium haynaldii. In Diatoms of the United States. Retrieved May 20, 2018, from

Species: Planothidium haynaldii

Contributor: Marina Potapova

Reviewer: Rex Lowe


Lange-Bertalot, H. (1999). Neue Kombinationen von taxa aus Achnanthes Bory (sensu lato). Iconographia Diatomologica 6: 276-289.

Patrick, R.M. and Reimer, C.W. (1966). The Diatoms of the United States exclusive of Alaska and Hawaii, V. 1. Monographs of the Academy of Natural Sciences of Philadelphia 13.

Schaarschmidt, G. (1881). Specimen phycologiae aequatoriensis. Magyar Novenytani Lapok 5(50):17-24.

Wetzel, C.E., Van de Vijver, B., Kopalová, K., Hoffmann, L., Pfister, L. and Ector, L. (2014). Type analysis of the South American diatom Achnanthes haynaldii (Bacillariophyta) and description of Planothidium amphibium sp. nov., from aerial and aquatic environments in Oregon (USA). Plant Ecology and Evolution 147 (3): 439–454. 10.5091/plecevo.2014.1058

Links & ID's

Index Nominum Algarum (INA)

Original INA

California Academy of Sciences (CAS)

Planothidium haynaldii CAS

North American Diatom Ecological Database (NADED)

NADED ID: 155031

Autecology Discussion

EMAP Assessment

The Environmental Protection Agency (EPA) western Environmental Monitoring and Assessment Program (EMAP) study was completed during the years 2000-2004 (see citations at bottom of this page). Over 1200 streams and rivers in 12 western states (Arizona, California, Colorado, Idaho, Montana, Nevada, North Dakota, Oregon, South Dakota, Utah, Washington and Wyoming) were selected for sampling based on a stratified randomized design. This type of design insures that ecological resources are sampled in proportion to their actual geographical presence. Stratified randomized design also allows for estimates of stream length with a known confidence in several “condition classes” (good or least-disturbed, intermediately-disturbed, and poor or most-disturbed) for biotic condition, chemistry and habitat.

EMAP Distribution

Planothidium haynaldii

EMAP Response Plots

Planothidium haynaldii

EMAP citations

Results are published in:

Johnson, T., Hermann, K., Spaulding, S., Beyea, B., Theel, C., Sada, R., Bollman, W., Bowman, J., Larsen, A., Vining, K., Ostermiller, J., Petersen, D. Hargett, E. and Zumberge, J. (2009). An ecological assessment of USEPA Region 8 streams and rivers. U.S. Environmental Protection Agency Region 8 Report, 178 p.

Stoddard, J. L., Peck, D. V., Olsen, A. R., Larsen, D. P., Van Sickle, J., Hawkins, C. P., Hughes, R. M., Whittier, T. R., Lomnicky, G. A., Herlihy, A. T., Kaufman, P. R., Peterson, S. A., Ringold, P. L., Paulsen, S. G., and Blair, R. (2005). Environmental Monitoring and Assessment Program (EMAP) western streams and rivers statistical summary. U.S. Environmental Protection Agency Report 620/R-05/006, 1,762 p.

Stoddard, J. L., Peck, D. V., Paulsen, S. G., Van Sickle, J., Hawkins, C. P., Herlihy, A. T., Hughes, R. M., Kaufman, P. R., Larsen, D. P., Lomnicky, G. A., Olsen, A. R., Peterson, S. A., Ringold, P. L., and Whittier, T. R. (2005). An ecological assessment of western streams and rivers. U.S. Environmental Protection Agency Report 620/R-05/005, 49 p.